Connection to a fieldbus
6.4 Communication via RS485
Inverter with CU240B-2 and CU240E-2 Control Units
136
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
Parameter identifier (PKE), 1st word
The parameter identifier (PKE) is always a 16-bit value.
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Figure 6-14 PKE structure
● Bits 12 to 15 (AK) contain the request or response identifier.
● Bit 11 (SPM) is reserved and always = 0.
● Bits 0 to 10 (PNU) contain parameter numbers 1 … 1999. For parameter numbers
≥ 2000, you must add an offset in the 2nd word of the parameter channel (IND).
The following table includes the request ID for telegrams between the master → inverter.
Table 6- 20 Request identifier (master → inverter)
Response
identifier
Request
identifier
Description
Positive Negative
0
No request
0
7
1
Request parameter value
1 / 2
7
2
Change parameter value (word)
1
7
3
Change parameter value (double word)
2
7
4
Request descriptive element
1)
3
7
6
Request parameter value
1) 2)
4 / 5
7
7
Change parameter value (word)
1) 2)
4
7
8
Change parameter value (double word)
1) 2)
5
7
1) The required element of the parameter description is specified in IND (second word).
2) Identifier 1 is identical to identifier 6, ID 2 is identical to 7, and 3 is identical to 8. We recommend
that you use identifiers 6, 7, and 8.
The following table includes the response ID for telegrams between the inverter → master.
The response ID depends on the request ID.